1. Field of the Invention
The present invention relates to a device for treating heart failure. More specifically, the invention relates to a cardiac harness configured to be fit around at least a portion of a patient""s heart.
2. Description of the Related Art
Congestive heart failure (xe2x80x9cCHFxe2x80x9d) is characterized by the failure of the heart to pump blood at sufficient flow rates to meet the metabolic demand of tissues, especially the demand for oxygen. One characteristic of CHF is remodeling of at least portions of a patient""s heart. Remodeling involves physical changes to the size, shape and thickness of the heart wall. For example, a damaged left ventricle may have some localized thinning and stretching of a portion of the myocardium. The thinned portion of the myocardium often is functionally impaired, and other portions of the myocardium attempt to compensate. As a result, the other portions of the myocardium may expand so that the stroke volume of the ventricle is maintained notwithstanding the impaired zone of the myocardium. Such expansion may cause the left ventricle to assume a somewhat spherical shape.
Cardiac remodeling often subjects the heart wall to increased wall tension or stress, which further impairs the heart""s functional performance. Often, the heart wall will dilate further in order to compensate for the impairment caused by such increased stress. Thus, a vicious cycle can result, in which dilation leads to further dilation and greater functional impairment.
Historically, congestive heart failure has been managed with a variety of drugs. Devices have also been used to improve cardiac output. For example, left ventricular assist pumps help the heart to pump blood. Multi-chamber pacing has also been employed to optimally synchronize the beating of the heart chambers to improve cardiac output. Various skeletal muscles, such as the latissimus dorsi, have been used to assist ventricular pumping. Researchers and cardiac surgeons have also experimented with prosthetic xe2x80x9cgirdlesxe2x80x9d disposed around the heart. One such design is a prosthetic xe2x80x9csockxe2x80x9d or xe2x80x9cjacketxe2x80x9d that is wrapped around the heart.
Although some of the above-discussed devices hold promise, there remains a need in the art for a device for treating CHF to prevent a remodeled heart from further remodeling and/or help reverse remodeling of a diseased heart.
In accordance with one aspect of the present invention, a cardiac harness is configured to fit about a patient""s heart. The harness comprises a plurality of individual modules that are assembled together to form the harness.
In accordance with another aspect, the present invention provides a cardiac harness configured to fit about a patient""s heart. A first module of the harness extends along a first portion of a circumference of the harness. A second module extends along a second portion of the circumference of the harness. The first and second modules are connected to one another.
In accordance with still another aspect, the present invention provides a cardiac harness configured to fit about a patient""s heart. A zip coupler is configured to selectively draw a first portion of the harness adjacent to a second portion of the harness.
In accordance with a further aspect of the present invention, a method of making a cardiac harness comprises providing a plurality of modules and connecting the modules to one another to form the harness.
In accordance with a still further aspect, the present invention provides a method of treating a diseased heart. A cardiac harness is provided and is configured to fit about a patient""s heart. The harness has a first end and a second end that are adapted to be coupled to one another. At least a portion of the harness is rolled about an axis. The rolled harness is placed adjacent a portion of the patient""s heart, and the harness is unrolled so that the unrolled harness fits about the heart.
In accordance with yet another aspect, the present invention provides a cardiac harness comprising a plurality of modules adapted to be coupled to each other. Each of the modules comprises a plurality of spring elements.
In accordance with still another aspect of the present invention, a cardiac harness is provided having a plurality of modules. Each module has a first edge, a second edge, and a zip coupling mechanism. The zip coupling mechanism selectively draws the first and second edges adjacent to one another.
In accordance with a further aspect of the present invention, a cardiac harness is provided. The cardiac harness is configured to fit about a patient""s heart, and has a base portion, an apex portion and a medial portion between the apex and base portions. The apex portion has a plurality of spiral shaped elongate members. Each spiral shaped elongate member is connected at one end to the medial portion and at the other end to a terminal member.
In accordance with a still further aspect of the present invention, a cardiac harness is provided having a base portion, an apex portion and a medial portion between the apex and base portions. The base portion has interconnected spring elements that are oriented so that the collective spring force around the circumference of the base portion is in a first direction. The medial portion has interconnected spring elements oriented so that the collective spring force around at least a portion of the circumference of the medial portion is in a second direction substantially different than the first direction.
In accordance with yet a further aspect, the present invention provides a cardiac harness having a central cavity for receiving a portion of a patient""s heart so that the harness contacts the wall of the heart substantially throughout the cavity. The harness has a plurality of protrusions extending inwardly so that interference between the protrusion and the wall of the heart aids retention of the harness on the heart.
Further features and advantages of the present invention will become apparent to one of skill in the art in view of the Detailed Description of Preferred Embodiments which follows, when considered together with the attached drawings and claims.